[dony409]

I need a list of wires under the hood that have power when the ignition is on. I am going to run power to my o2 sensor and would like to know where the easiest one is.

 

[GLHNSLHT2]

Don't power it off an ignition source, you'll draw too much current and at best possibly blow fuses and at worst start a fire. Run power from the battery to a relay, then use the relay to power your stuff, and turn the relay on and off with an ignition source.

 

[dony409]

What is the simplest way of going that route? I'm not good with this kinda stuff... What wire should I run the relay off of?